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By Errol Ladner

The application of large-diameter bore holes in underground operations at Heath Steele was first tried in February, 1975. Since that time, 90,000 feet of 6-l/2-inch holes have been drilled, primarily in open blasthole stoping, for a total of 1.4 million tons, 37% of underground production. This paper deals with a review of drilling with conventional percussion longhole drills, a practice which is still utilized at Heath Steele, and the changeover to accommodate the use of larger blastholes in underground operations. The discussion will include layouts for 2-inch-diameter blasthole stope blocks, 6-inch-diameter stope blocks, trials for I. T.H. (in-the-hole) stope rooms, and drill pat/ems, drilling and performance. The complexity involved in the development, drilling and blasting of 2-inch blastholes is overcome by the over-all simplicity of drilling and blasting in I. T.H. stopes. This has made the practice of open blasthole stoping more economical and efficient. The future indicates an increase in the company's I. T.H. program. Investigations are being undertaken regarding longer holes to decrease development costs. A VCR stope is also being developed for trial.

Jan 1, 1979

By Carlos Nieble

Ferteco Mineracao, belonging to the CVRD group, is one of the several iron ore mines in the south east of Brazil. Some of these mines have pit walls of over 350-m height and operations under difficult geo-technical conditions are steadily increasing. In order to mine the 15 million tonnes of high grade hematitic ore remaining in the Fabrica pit, Ferteco had to deal with the following restrictions: Warrant power to its concentrator and pellet plant, relocate the load-out rail road loop, stabilise a poor phillyte slope, relocate a creek on a bench, lower the water table and mine at maximum angles at a slope with phillyte and loose itabirites directly under the rail road loop. Considering these aspects, 3 stages of operations were designed, considering a safe operation, but with the lowest possible security factors at the last mining stage, before the pit would be filled in again with tailings. Stage one above the rail road loop and below the high tension power mast, where the poor phillyte slope was secured by a flexible retaining wall, using old rails and anchors up to 27 meters (80ft) with a working pressure of up till 30 tonnes and stage two with different slope angles, and deep wells, high wall blasting perpendicular to the highwall with relief holes and rerouting the creek in steel half culvert and stage three, the filling in with tailings and recuperation of the deep well pumps. Following studies and analysis were made: Geotechnical and geological studies of all rock formations including rock strength test, a hydrological study to define the lowering of the ground water level, slope stability analysis for every bench and all possible combination of benches, definition of blasting parameters close to the pit slope, a monitoring plan, including topographical movements, vibrations due to blasting, piezometers and pressure cells as well as a plan how to fill up the pit again with tailings in combination with the rising of the ground water level. A close co-operation between the geo-technical consultant, pit operations, the blasting contractor and the geological department resulted in an operation without any incidents, lowering the pit with an additional 3 benches and mining an additional 5 million tonnes of high grade ore.

May 1, 2003

By D. Pérez Escobar

Multiphase steels are quite sensitive to hydrogen embrittlement. Laboratory tests to evaluate this often use electrochemical, charging to introduce hydrogen into the sample, but damage purely caused by hydrogen charging has to be avoided. A ferrite-bainite steel, was charged using various conditions to identify when surface blisters occurred. Samples were also checked for internal, damage by electron microscopy. This study was repeated for three other multiphase steels and pure iron. An HSLA steel, was found to be more resistant whereas pure iron was quite susceptible to internal, hydrogen damage. For al, industrial, steels, cracks concentrated in the middle of the sample were attributed to inclusions and segregations, inherent to production.

Jan 1, 2010

By J. F. Magee

THERE is nothing new about drag-line dredging for placer gold. The use of the separate unit for excavating preceded the large barge with bucket-line excavator mounted upon it, which has developed to a high state of perfection through use in every part of the world. But at present there is a vogue for a small, inexpensive plant to work economically the shallower gold gravel deposits that the bucket-line dredges do not work. The dragline dredge consists of the drag-line excavator, on caterpillar mounting on the edge of the dredging pond, which feeds the gravel to the washing plant, mounted on a floating barge in the pond. There have been more than twenty-five such plants built and operated in central and northern California and an unknown number in other States. There have been variations in details of design but the essentials are similar in all. I wish to describe the operation of a typical drag-line dredging plant, that of the Wyandotte Gold Dredging Company on the Farnan Ranch in the Oroville district. This organization of six active partners built their first plant on Wyandotte creek in the autumn of 1933. The operation was successful due to wise management, which was based upon good plant design and proper principles of operation. The partners elected one of their number, H. F. England, as manager with full control and responsibility. This plant and operation furnished the pattern for many subsequent ones.

Jan 1, 1937

By Chris Twigge-Molecey

"Over the last 50 years there has been a dramatic evolution in the metallurgical engineering field in Canada. In the 60s the field was dominated by large American and UK groups, often selling major process and equipment packages. The local content was limited to wrap around facilities and the civil and structural work. The mining and metallurgical companies had strong internal teams to lead these projects. Over the decades and business down cycles the large foreign contractors disappeared or re-structured and the mining companies largely shed their engineering and project management groups. The resulting gap was filled by a cadre of local specialist engineering companies, some of whom have grown to be world leaders in the field. The paper traces this evolution and examines the underlying causes and consequences."

Jan 1, 2015

By Y. Serres

In the past, conventional reflection seismic techniques were not very successful when applied to typical mining exploration: they lacked resolution in the shallow range or were not cost effective. By combining a light earth tamper source, special geophones and field procedures, a stacking process of the returning seismic events using a microprocessor system, and a sophisticated sequence of adapted digital data processing, Mini-Sosie achieves high resolution in the 100-ft to 4000-ft range. Additional advantages result from the very quiet nature of the source and flexibility of the system. Although Mini-Sosie might be used in the refraction mode, or for well velocity logging, it has found its main applications with the reflection technique.

Jan 1, 1978

By L W. Morley

The Division is concerned with physical methods as applied to geo-logical research and mapping. An at-tempt is made to describe long-term goals, illustrated by examples of projects in the fields of aeromagnetic interpretation, palaeomagnetic re-search, Pleistocene and groundwater geophysics, seismic surveying, electromagnetic research and instrument development. Cooperative projects in surveys and research, with universities, private companies and provincial organizations, are frequently undertaken. An outstanding example of this is the recently approved Federal-Provincial Aeromagnetic Survey Plan, the purpose of which is discussed both from an economic and a scientific point of view. HISTORY OF THE DIVISION M AGNETIC, electrical, seismic and gravity methods, as a means of extending the geologist's sphere of observation beyond the head of his hammer, came into wide-spread use for the first time after World ?war I. Interest in these methods was aroused amongst geologists of the Geological Survey and, in 1928, a group of these geologists and university

Jan 1, 1963

By John I. Sharpe

Masses of pyritic copper and zinc ores are entrapped along the contact zone between two volcanic groups in the Matagami area. The upper limits of the sulphide concentrations tend to form concordant contacts against lava or cherty tuffite units of the younger group; the lower extremities tend to either follow transverse structures or merge with zones of dispersed sulphides. The sulphides are deformed and intruded by folded dykes. Close relations between metallization boundaries and volcanic lithology and stratigraphy, and a preliminary investigation of the fabrics and crystallization temperatures of the sulphide masses, suggest that the copper and zinc (but; not necessarily all the iron sulphides) were emplaced at h1gh temperatures during volcanism in near-surface lithological-stratigraphic traps. Introduction T HE Matagami area is centered 120 miles north of the Val d'Or and Noranda camps in north-western Quebec. For the present purpose, it is considered to comprise a 155-square-mile area in Isle-Dieu, Galinee and Daniel townships which encompasses the main sulphide masses. Airborne geophysical surveys within this area in 1956 led to the discovery of a large sulphide body -the.

Jan 1, 1965

By W. Hawker, A. M. Ivana

"Pressure oxidation is used to liberate gold from refractory sulphide ore and concentrates with over fifteen autoclaves in operation. Despite the importance of pressure oxidation, the autoclave chemistry and chemical thermodynamics are not well established. For example, there is no consensus on aqueous iron speciation or stability of jarosite phases. Additionally, there remains questions about basic ferric sulphate formation and stability. In addition to a review of the current state of knowledge, a methodology to study the ferric precipitation reaction and relate the results to chemical thermodynamic predictions is presented which will be used to accurately define the phase boundaries of the iron precipitates in the future (hematite, jarosite and basic ferric sulphate).INTRODUCTION With declining availability of orebodies that respond to simple leaching conditions, pressure oxidation has become a prevalent technology to liberate gold locked in sulphide mineral matrices. Gold pressure oxidation was established 32 years ago, with McLaughlin being the first facility in 1985 (Thomas & Pearson, 2016). Pressure oxidation is carried out at elevated temperatures ranging from 180 to 240°C as shown in the summary of operations in Table 1 (Ruonala et al., 2016; Fleming, 2010).A considerable amount of research has been done to study iron solubility and precipitation under autoclave conditions (Tozawa & Sasaki, 1986; Umetsu et al., 1977; Sasaki et al., 1993; Fleuriault, 2016; Cheng & Demopoulos, 2004; Papangelakis et al., 1994; Yue et al., 2003). These reports provide a description of the process chemistry and iron behaviour in the autoclave. However, there remain questions about the type and stability of aqueous species and solid phases. This detailed information is required to build a robust chemical thermodynamic model of the system, allowing for equilibrium and kinetic reaction limitations to be discerned."

Jan 1, 2017

By K. Gardner

"Many deposits have a geological model developed early in the project stages, which is not always reviewed or modified as the project matures and production commences. Conversely, ongoing pressures, due to a combination of declining head grades, a push for increased revenue and a multitude of other reasons, leads to processing plant modifications, with the primary aim being to increase production. Often, the ore deposit knowledge is not sustained or developed during the operational stages to the level carried out during the prefeasibility and feasibility study phases. This results in the variability within the deposit being poorly understood and a lack of data and knowledge being available to support (and ideally optimise) operations particularly in an environment where the flow sheet has changed and ore feed requirements are complex.INTRODUCTION This paper presents a case study of ore deposit knowledge development and corresponding process plant operating strategy at the Ladolam Gold Deposit, commonly referred to as the Lihir gold deposit in Papua New Guinea. The gold deposit is located in a tropical equatorial climate on the east side of Lihir Island in the New Ireland Province of Papua New Guinea. Gold mineralisation was discovered in 1982, and was followed by a major exploration campaign by a joint venture between Kennecott (Rio Tinto) and Nuigini Mining Limited. The first drillhole was drilled in 1983, and after an extensive period of drilling consisting of 343 holes for 83,500 m, the final Feasibility Study was completed in 1992. The feasibility study was based on a Reserve base of 37.9 Moz in refractory sulphide ore, with gold extraction proposed to occur via whole ore pressure oxidation due to the refractory nature of the mineralisation. The Lihir Special Mining Lease (SML) was granted in 1995 to a new PNG company – Lihir Gold Limited, and Rio Tinto established Lihir Management Company to develop and operate the mine on behalf of LGL. Mining and processing of the deposit commenced in 1997. Newcrest Mining Limited purchased Lihir Gold Limited in August 2010, and subsequently completed a major plant upgrade including the installation of additional grinding, autoclave and carbon-in-leach capacity. Post commissioning of the upgrade, Newcrest has continued to increase throughput and production. A reinvigorated ore body knowledge development program has significantly assisted this process in identifying operating strategies for the process plant and delivering recovery improvement projects to address declining head grade and recovery due to increased stockpile feed and flotation circuit use."

Jan 1, 2017

By T. R. Skerry, H. P. Hudson, T. E. Warren

"ALTHOUGH coal is generally the cheapest fuel on the basis of heating value it has been at a disadvantage in competition with other fuels because means have not been available for efficient •Conversion of its thermal energy to mechanical work. Taking the •railway application •as an example, the cost of Diesel oil is about three times that of its thermal equivalent in coal, but the overall efficiency of a Diesel locomotive is about five times that of a coal-fired steam locomotive. Accordingly, the Canadian railways are replacing all coal-fired steam Locomotives, as they are retired from service, with Diesel units. This conversion in itself represents a major loss to the coal industry because the value of railway fuel is approximately 130 million dollars per year, and there are other applications in the medium power range where oil is displacing coal. There is, therefore, a strong incentive to attempt development of an efficient coal-burning engine.Coal has never been a promising fuel for reciprocating internal combustion engines because of the time required for its combustion in pulverized form . This is not less than one-tenth of a second so that the speed of such an engine would have to be very slow. There are also serious difficulties of a mechanical nature arising from the necessity for intermittent combustion and the use of close-fitting pistons."

Jan 1, 1952

By R. Guimarães, L. Silva, J. Milboume

The São Bento concentrator was built by Gencor in 1985 to treat refractory gold-bearing flotation concentrate. The plant was the first commercial application of pressure oxidation for refractory gold ore following about a year after the first use of pressure oxidation on a whole ore at Homestake's McLaughlin operation in California. Ore from the Sao Bento mine is remarkably consistent in gold grade and arsenic and sulphide concentration as is typical in banded iron formations (BIF) (l). Gold content is approximately 9 g/t with approximately 30 - 40% free milling. The balance is associated with arsenopyrite and pyrrhotite. An expansion of both process facility and mine was undertaken between 1996 and 1998, raising the treatment capacity from 32,000 t/mo to 45,000 t/mo.

Jan 1, 2004

By K. Miao, W. Mu, M. Sharma, A. Haas, N. Dogan

"The ever increasing demand for cleaner steels with low inclusion content has highlighted the limits of our current knowledge for controlling and predicting inclusion agglomeration and removal during liquid steel processing. Key knowledge gaps in this area result from the complex nature of the problems associated with measuring and visualizing the phenomena studied. Confocal scanning laser microscope (CSLM) allows for continuous in situ observation of micron-size samples in real time, at high resolution, under conditions relevant to the steelmaking process. This paper summarizes some of recent CSLM applications in our laboratory to illustrate the methods of analyzing transient behavior. The reaction between inclusions and slag is given as an example. The dissolution rate of calcium aluminate inclusions in CaO-SiO2-Al2O3 slags has been studied at elevated temperatures: 1500, 1550 and 1600°C as well as thermodynamic/kinetic analysis. It is found that total dissolution time decreased with increasing temperature. The rate limiting steps are discussed. It is shown that the diffusion through a product layer is responsible for dissolution at 1500°C. At higher temperature, dissolution is most likely controlled by both boundary layer diffusion and chemical reaction at the slag-inclusion interface. In this paper, the evidence for and against the theory will be critically examined and repercussions of the theory to steel refining processes will be discussed.INTRODUCTION Inclusion formation during liquid steel refining is an unavoidable consequence of current ladle steelmaking processes. The nature and quantity of the inclusions formed in steel is critical in steelmaking, as it affects both productivity through clogging, and downstream physical properties of the steel. It is therefore crucial to better understand and control the formation, agglomeration and dissolution behaviour of inclusions in a slag in order to improve the removability of inclusions from liquid steel. Most research (Sandhage & Yurek, 1988; Sandhage & Yurek, 1990a; Sandhuge & Yurek, 1990b; Sandhuge, 1991) relevant to the kinetics of inclusion removal has been obtained by using a technique where simulated inclusion material (ceramic rods) is dipped in slag and the dissolution rate is measured. While much has been learned using this approach, the difference in scale from bulk materials to inclusions is likely to have a significant bearing on the dissolution kinetics of inclusions in a slag and will certainly result in a very different influence of capillary effects. Further, the data obtained using an indirect (dip test) procedure relies on a comparison of the initial and final conditions of a sample rather than in-situ observation which can be achieved in a confocal microscope in real time."

Jan 1, 2017

By H. O. Olsen

"GeneralTHE IRON ORE at Marmora is a replacement deposit of Precambrian limestone and is overlain with Palaeozoic limestone. It is a low-grade magnetite deposit and the ore will require concentration be-fore it can be used economically for the production of iron and steel.Present plans estimate an annual production of 500,000 tons of concentrate in the form of pellets. This will require mining approximately two million tons of ore and\ waste annually. Shipment of pellets from Marmora to a ship-loading dock at Picton will be made by rail on a year-'round basis. Shipments from Picton to the Lackawanna plant of the Bethlehem Steel Company at Buffalo, N.Y., will be carried on during the Lake shipping season.LocationThe mine, located a mile southeast of Marmora village in Hastings county, Ontario, is 31 miles north of Belleville and 3•7 miles east of Peterborough. Marmora is 130 miles from Toronto and 150 miles from Ottawa. Highway No. 7 passes half a mile north of the mine and Highway No. 14 half a mile west of the mine. The Canadian National railways' branch line between Trenton and Bancroft passes through the property just east of the open pit.HistoryThe Ontario Department of Mines conducted an airborne magnetic survey of the district during 1948 and 1949. Maps of this survey were released to the public early in 1950. Bethlehem representatives carried out ground surveys in the Marmora area shortly thereafter and in June, 1950, commenced diamond drilling."

Jan 1, 1955

By R. D. Westervelt

IN JULY 1954, the first iron ore from the deposits in the Knob Lake vicinity was mined and shipped to Seven Islands. The beginning of the production may well be the greatest advance in Canadian economy in the past fifty years. In 1955, the Canadian iron ore output was more than twice that of 1954, an in-crease due principally to the iron ore shipments from the Knob Lake area. Previous to this, Canada's iron production was 1.85 per cent of the world's output. Now, this percentage has risen to approximately 5.5 per cent and shows every indication of increasing further as the production rate from the area is increased. In 1955 the Iron Ore Company of Canada shipped over 7 million tons of iron ore and expects to ship over 10 million tons in 1956. Present facilities may be enlarged to handle up to 20 million tons per year. If the expected I 0 million tons per year are exported, Canada's iron exports will be second only to her wheat and newsprint exports. Before production began from the Knob Lake deposits, years of development were necessary in the area. Geologists spent several summers mapping the general area in order to unravel the complicated stratigraphy and petrology. Particular attention was paid to the mapping of the iron formation and all stages of alteration from fresh iron formation to ore were observed.

Jan 1, 1957

By Robert J. Shank

This paper describes the Federal Government assistance available for northern mining development. The paper commences with a discussion of why the Federal Government should give assistance to northern mining development. It then uses a hypothetical case of a company which has a property it wants to develop to list the sectors within the . Federal Government that would have to be consulted in order to obtain federal financial assistance. The paper also outlines the type of information a company must be willing to provide the government in order to qualify for such assistance.

Jan 1, 1978

By G. Granata, C. Tokoro, M. Matsuoka, K. Horiuchi

"Given the high demand of copper and the lack of new high-grade deposits, low grade copper ores containing copper oxides and refractory sulfides need to be processed as well. However, in order to recover copper from refractory copper ores, the leaching performances should be improved. In this study, we investigated the effect of the mechanical activation in the leaching of copper from covellite. The influence of a mechanical treatment by planetary ball milling on leaching rate in sulfuric leaching media was evaluated by using X-ray diffraction (XRD), mineral liberation analysis (MLA) and X-ray absorption fine structure (XAFS). Results showed a significant increase in copper leaching from around 50%up to 100% along with an improvement of the leaching kinetics when using planetary ball milling. XRD spectra showed the disappearance of the covellite peak from (101) face, thus suggesting the amorphization of covellite associated with the use of planetary ball milling. XAFS results showed that the coordination number of Cu changed from 6 to 3, thereby confirming the effectiveness of the mechanochemical effect.INTRODUCTIONDuring the last decades, while the copper grade in copper ores has been decreasing, the concentration of impurities such as arsenic tends to increase, thus requiring for the processing of low grade copper ores. For a suitable processing of copper minerals, hydrometallurgical processes are preferable due to the lower costs, the lower environmental impact and the easier implementation (Watling, 2006). However, for an economical recovery of copper, the leaching performances must be improved.Among the recent advancements in leaching technologies, the mechanochemical activation allows for an improvement of the leaching performances by means of high-intensity grinding(Mohammadabad et al., 2016). In the first place, the improvement is the result of the dramatic decrease of particle size, which results in an increase of the mineral surface area and the consequent enhancement of leaching kinetics. Furthermore, the intense mechanical stress due to the high-intensity grinding could induce the rupture of the crystal structure producing a decrease of crystallinity. Such changes of the mineralogical structure, also known as mechanochemical effect, can lead to more leachable mineral, thereby resulting in a greater dissolution of copper. Last but not least, whereas the mineral surface might undergo passivation during leaching, the high-intensity grinding can continuously refresh the surface of the mineral, thus exposing portions of unleached bulk mineral."

Jan 1, 2017

By SangHyeok Han

Selecting the best possible cranes and identifying spatial conflict-free locations on sites can result in productivity and safety improvements for large-scale industrial construction projects. In the current practice, experienced lift engineers select cranes based on the heaviest lift and/or the largest lifting radius of the identified crane. This practice is relatively time-consuming, and optimization of the crane?s use and location is also difficult. There are many factors which need to be considered during the crane selection process, a reality which further complicates the process. This paper presents a framework which aims at developing a decision support system to enhance the crane selection process and collision-free path planning for large-scale construction projects. This paper utilizes an innovative crane selection matrix in order to establish a process for optimized crane selection for construction projects. The study considers more than 40 different factors in order to reduce time and improve safety for crane operations. Following finalization of crane type (mobile crane versus tower crane), a visualization model to simulate crane operation and identify collision-free crane operation paths is proposed. This process can assist project managers to plan the lifting process more effectively and efficiently. A case study-based approach was utilized to demonstrate the proposed methodology. The methodology was tested in the planning and construction process for boiler house structures in Mannheim, Germany. The project entailed numerous challenges: one of the major tasks was to lift a 102-ton load on the top of the boiler structure through crane collaboration; space limitations on site also presented several challenges related to crane selection, location, and operation processes. Based on the project constraints, the proposed crane selection framework, and the visualization models, two tower cranes were selected and successfully implemented in the case study.

Aug 1, 2013

By Jirí Faltus

The paper deals with studying the impact of structural properties and anodizing of surface on the corrosion properties of extruded rods from commercial aluminium alloys: AA6082, AA6262, AA6012, AA2007 and new lead-free aluminium alloys AA6023, AA2015 and AA2111B. Samples were exposed to the corrosive atmosphere NSS, AASS in the chamber by EN ISO 9227. Surface of samples were either in the original state or anodizing by selected mode. The depth of corrosion attack and the form of corrosion attack are evaluated depending on the type of alloy, the metallurgical condition and surface treatment of the samples.

Jan 1, 2015

By Fazel G. Jahromi, Ahmad Ghahreman

"Several studies were performed on the atmospheric leaching of copper sulfide minerals in the presence of activated carbon and a new catalyst, AF 5. AF 5 is a carbon based catalyst with similar properties to those of activated carbon however much better mechanical properties. The activated carbon surface chemistry has been investigated in various studies; however the connection of the surface chemistry of activated carbon and AF 5 with the sulfide minerals during the atmospheric leaching process is not well-understood yet. Based on the surface analysis, AF 5 showed higher surface area than activated carbon (AC). Adsorption and oxidation of copper, arsenic and iron ions in the presence of different activated carbon were investigated. Adsorption properties of both catalysts were similar and 18-24% of iron, 12-18% of copper and 10% of arsenic adsorbed on the catalysts surface form 5 g/L Fe(III) and Cu(II) and 2 g/L As(III) at 80°C. In oxidation experiments, both catalysts reduced Fe(III) and Cu(II) ions and re-oxidized the reduced species in the presence of oxygen and oxidized As(III) ions. The addition of oxidizing ions can enhance the oxidation process kinetics and increase the catalytic capability of carbon.INTRODUCTION Hydrometallurgical processes of copper sulfide concentrates are under development and various different methods have been proposed to increase the atmospheric leaching rate of copper sulfide minerals. These methods include using different media, reagents, and catalysts. Among different methods, leaching of the copper sulfide minerals in the chloride media has some advantages over sulfate media. Smaller scale of operation, increased leaching rates, and lower sulfate formation are some of the benefits of the chloride leaching media over other similar media. Moreover, using ferric and cupric ions as oxidants and utilizing activated carbon as a catalyst has been proven to enhance the leaching rate of copper sulfide minerals effectively. Activated carbon (AC) and AF 5 (micro porous carbon based catalyst) are two of the most efficient and practical catalysts in copper sulfide leaching processes. AC can enhance the copper recovery of enargite in chloride media from 69% to 92% after 96 hours of leaching under the similar conditions (Jahromi & Ghahreman, 2016). It has been shown that AC at acidic pH can generate hydrogen peroxide in the presence of oxygen which can leach copper minerals (Ahmumada et al., 2002)."

Jan 1, 2017